basline.scss

$base-font-size: 16px;
$base-line-height: 1.5;
$rhythm-line: round($base-font-size * $base-line-height); // in pixels
$caps-height: 0.68;


@function calculate-lines-for-size($font-size) {
	// Returns unitless value
	@return ceil(($font-size + 0.001) / $rhythm-line);
}

@function calculate-line-height($font-size) {
	$lines-count: calculate-lines-for-size($font-size);
	@return round($rhythm-line * $lines-count);
}

@function calculate-padding-top($font-size) {
	$line-height: calculate-line-height($font-size);
	@return ($line-height - ($font-size * $caps-height)) / 2;
}

@function calculate-margin-bottom($font-size) {
	$padding-top: calculate-padding-top($font-size);
	@return $rhythm-line - $padding-top;
}

@mixin vertical-rhythm($font-size: $base-font-size) {
	font-size: round($font-size);
	line-height: round(calculate-line-height(round($font-size)));
	padding-top: round(calculate-padding-top(round($font-size)));
	margin-bottom: round(calculate-margin-bottom(round($font-size)));
}